New Flow Battery Powered by Solar Doesn’t Need a Gigafactory

Flow battery technology holds the promise to make solar more viable — without a battery gigafactory. Energy stored during the day on an almond farm is used at night to operate a pump that can irrigate about 300 acres of almond trees.

An almond farm in the Turlock, CA area might not sound like the most likely place for new flow battery technology, but that is exactly where EnverVault decided to locate a demonstration-size iron-chromium redox flow battery. Its capacity is one megawatt-hour of energy for four hours and it is situated near a 150-kilowatt solar system and an electric irrigation pump.

Energy stored during daylight hours can be used to operate the pump at night to irrigate about 300 acres of almond trees.

At the dedication ceremony, CEO Jack Pape, said, “Our mission is to safely and reliably deliver grid flexibility to the California market and to the world market.”

An electrolyte is pumped through a stack of electrochemical cells to generate electricity. The technology is housed in huge steel cylinders; two of them placed side by side are about the size of two shipping containers stacked vertically. The electroylyte is mostly water, which is obviously abundantly available and at very low cost.

Other advantages of its flow battery are that it is less flammable than lithium-ion batteries and non-toxic. They do require more space to be installed due to their large size. The technology can scale, however, because adding more towers and cells is fairly easy.

We’ve been hearing a lot about Tesla’s gigafactory, but EnerVault’s flow battery is relatively simple in design and uses more common materials. “I don’t have to have a factory. All I need to build is the cells and stack – there is no gigawatt factory required. I am going to be the big energy storage guy because the tanks come from a supplier, the pumps come from a supplier. Power conditioning and controls – all arrive at the job site with my cells and stacks, so I don’t have to inventory. I have a very cash efficient business model, with 80% as pass through. We will make an announcement shortly with respect to a partner who can build these facilities at low cost. This scales rationally and fairly easily – there’s no $5 billion gigafactory,” explained CEO Jack Pape.

Pape started the grid storage company in a Sunnyvale garage in 2008. He is also a former executive at SunPower, and some other EnerVault employees are from the PV company also. (A former VP of manufacturing at Tesla is also on board at Envervault.)

US Invest, Oceanshore Ventures, Mitsui Global Investment, Total Energy Ventures, and TEL Venture Capital are some of EnverVault’s backers. Analyst Sam Jaffe said the market for energy storage batteries could be over $20 billion by the 2020s.

Though Silicon Valley is known as a place where software engineers constantly pound out code, chemical engineering is a little more challenging than developing the next app.

“Nature doesn’t like to store energy,” explained Craig Horne, a co-founder of EnerVault. “That energy is going to want to release. And that’s why energy storage has always been such a challenging technology to commercialize because, in a way, you’re defying nature.”

If successful on a large scale, energy storage is also going to be much more impactful than the next social media site. I would be curious to see if there is any viability for a flow battery system to work with CSP, rather than thermal storage.

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